1. Field of the Invention
The present invention is directed to providing a Bluetooth terminal, a Bluetooth relay, and a Bluetooth system that can determine a network configuration of the Bluetooth automatically and transfer to an optimal waiting state.
2. Description of Background Art
A communication system (intercom) which enables wireless communication between riders driving on two-wheel vehicles with each including a relay terminal on the vehicles and a headset including a speaker, a microphone, and a transceiver provided on a helmet of the rider so that a rider and a passenger on the same vehicle, or riders on the different vehicles can communicate each other by air via the relay terminals is disclosed in Microfilm in JP-UM-A-62-155535.
In addition, JP-A-2001-148657 also discloses a technology in which a Bluetooth is mounted to a headset and a portable phone so that the riders of two-wheel vehicles can communicate via the portable phones in a hands-free manner and the portable phones are remote-controlled from the headsets. By mounting a relay terminal having a remote control function in the vicinity of a throttle grip of the vehicle and mounting the Bluetooth in the relay terminal, the rider can remote control the portable phone from the relay terminal which is superior in operability than the head set.
In the Bluetooth, there are defined two types of connections as a physical RF link; a Synchronous Connection Oriented: SCO and Asynchronous Connectionless: ACL. The SCO link is a point-to-point link of a call connection type created between a master and a specific slave, and is used mainly for transferring voice data. One single master can have three SCO links at a maximum to the same slave or different slaves. The ACL link connects between a master in one Piconet and all the active slaves in a packet switching manner. The master can switch the packet with a given slave in a slot unit using a slot which is not reserved for the SCO link. The ACL link is mainly used for data transfer.
In a Bluetooth system, if a reduction in power to be consumed in respective wireless terminals is wanted, it is preferable to disconnect an ACL link together with the disconnection of an SCO link when transferring to a waiting state after having terminated communication through the SCO link. On the other hand, in the Bluetooth system, when establishing a new SCO link, the link can be established in a shorter time from the waiting state in which the ACL link is established than from the waiting state in which the ACL link is not established.
Under such an environment wherein only a headset 11 and a portable phone 12 exist as the Bluetooth system as shown in FIG. 1, and there exists no vehicle-mounted relay terminal, the rider can access the portable phone 12 by operating the headset 11 directly. Therefore, the headset 11 can response immediately to the operation of the rider, and can generate a response sound which indicates that the operation is accepted.
In contrast, as shown in FIG. 2, in a system configuration in which a vehicle-mounted relay terminal 13 is interposed, and all the operations are performed from the relay terminal 13, operating sounds in response to the operation performed to the relay terminal 13 are sent to the headset 11 using the SCO link. Therefore, there arises a technological problem in which there exists a time lag in the generation of the operating sounds in response to the operation of the relay terminal 13 that is done by the rider unless the ACL link is established between the relay terminal 13 and the headset 11.
If the headset 11 can recognize whether a terminal on the partner side is the portable phone 12 or the vehicle-mounted relay terminal 13, such a technological problem can be solved by employing such a control that the ACL link is disconnected together with disconnection of the SCO link when the terminal on the partner side is the portable phone 12, and the ACL link is not disconnected even when the SCO link is disconnected when the terminal on the partner side is the relay terminal 13.
However, as is well known in the Bluetooth technology, the respective terminals identify the type or the function of the terminal on the partner side by a connection profile mounted on the terminal on the partner side. Thus, since only a multi-purpose headset profile or a hands free profile is mounted as the connection profile which enables communication with the headset in the relay terminal and the portable phone, it is difficult to recognize that the terminal on the partner side is either the portable phone 12 or the vehicle-mounted relay terminal 13 by the headset 11.